Field of the Invention
The invention relates to an ink-metering device in a printing press having a film disposed between an ink roller and metering elements associated with the ink roller, each of the metering elements having at least one support rib indirectly resting on the ink roller via the film, the film having low-wear zones covering the support ribs.
In the published German Patent Document DE 43 41 243 C2, there is described a metering device of a printing press having a film with low-wear zones in the form of a metallized coating or a layer of carbon fiber-reinforced plastic material. This construction of the film represents considerable progress in the state of the art with respect to the service life thereof over films having no low-wear zones. It has been demonstrated, however, that the service life of such ink duct films, wherein the metal or carbon forming the low-wear zones is deposited in layers on the base material of the film and is, for example, vapor-deposited in multiple steps, is still unsatisfactory. On the one hand, the attainable layer thickness of the low-wear zones produced in this manner is very slight, so that, despite having an increased abrasion strength compared with that of the base material of the film, the low-wear zones are gradually ground down to the base material of the film by the rotating ink-duct roller within a given length of time that the film is in use. On the other hand, the attainable adhesion of the low-wear zones to the base material of the film produced in this manner is so slight that the low-wear zones break off in patches from the base material of the film. Both of these effects, which are dictated by the production process, cause the low-wear zones to lose the desired effect thereof in a comparatively short time and no longer retard the wear of the film overall.
In U.S. Pat. No. 3,318,239, a device with a three-layer ink duct lining is described which facilitates the cleaning of the ink duct. The ink duct includes a single ink knife but no metering elements. The ink duct lining has a thin, flexible vinyl layer, a tissue paper layer, and a cardboard layer, and has no low-wear zones.
It is an object of the invention to provide an ink-metering device in a printing press that assures reliable replicability of the metering setting.
With the foregoing and other objects in view, there is provided, in accordance with one aspect of the invention, an ink-metering device in a printing press having a film disposed between an ink roller and metering elements associated with the ink roller, each of the metering elements having at least one support rib indirectly resting on the ink roller via the film, comprising low-wear zones provided on the film for covering the support ribs, the low-wear zones being formed as wirelike bodies joined to the film.
In accordance with another feature of the invention, the film has a multilayered construction.
In accordance with a further feature of the invention, the film has a substrate layer and a filmlike securing layer, the wirelike bodies being secured on the substrate layer of the film by the securing layer of the film.
In accordance with an added feature of the invention, the film has a substrate layer and a securing layer, the wirelike bodies being secured on the substrate layer of the film by the securing layer, the securing layer being pourable into spaces between the wirelike bodies.
In accordance with an additional feature of the invention, the wirelike bodies are embedded in solidifiable material forming the film.
In accordance with yet a further feature of the invention, the wirelike bodies have a curved contoured profile.
In accordance with another aspect of the invention, there is provided an ink-metering device in a printing press having a film disposed between an ink roller and metering elements associated with the ink roller, each of the metering elements having at least one support rib indirectly resting on the ink roller via the film, comprising a plurality of low-wear zones provided on the film for covering the support ribs, the plurality of low-wear zones being disposed so that a zonal spacing between adjacent low-wear zones is less than a total width that includes two support widths of adjacent support ribs.
In accordance with a further aspect of the invention, there is provided an ink-metering device in a printing press having a film disposed between an ink roller and metering elements associated with the ink roller, each of the metering elements having at least one support rib indirectly resting on the ink roller via the film, comprising a plurality of low-wear zones provided on the film for covering the support ribs, the plurality of low-wear zones covering a support width of one and the same support rib.
In accordance with another feature of the invention, the support width of the support rib is at least as large as a center-to-center spacing between two adjacent low-wear zones.
In accordance with a further feature of the invention, all of the low-wear zones of the film are disposed at an identical spacing from one another.
In accordance with a concomitant aspect of the invention, there is provided a printing press having at least one ink-metering device with at least one of the foregoing features.
The service life of an elastic film formed in the foregoing defined manner is very long, and abrasion from the low-wear zones in the region of contact with the ink roller is very slight. Thus, high replicability of the setting or adjustment of the relative position of the metering elements to the circumferential surface of the ink roller and of the amount of ink allowed to pass through the metering elements on the circumferential surface of the ink roller is assured.
A setting or adjustment of the metering elements that is memorized electronically or noted in writing and that corresponds to a printed image of a printing job can be re-used, in a repeat job that has the same particular printed image without requiring correction as in corresponding devices of the prior art. The wirelike bodies that form the low-wear zones may be formed of metal, metal alloy, plastic material, or some other abrasion-proof material. The wirelike bodies can be joined to the film by being embedded in the film or secured to the film.
The film may be embodied in multiple layers. The multilayer film can have various types of film layers. For example, a first film layer may perform a function that stabilizes the film, while a second film layer may perform a function enabling the integration of the wirelike bodies with the film. The wirelike bodies may also be enclosed between two identical film layers of the multilayer film. Preferably, one of a plurality of film layers is a securing layer for joining the wirelike bodies to the film.
In a further embodiment, the wirelike bodies are secured on a substrate layer of the film with a film-like securing layer of the film. By forming the film of at least two mutually joined film-like film layers, advantages in terms of production technology are attained. For example, the film layers can be adhesively joined or welded together, enclosing the wirelike bodies therebetween. The wirelike bodies themselves may be firmly joined to a single one of the film layers or to both film layers. Provision may also be made for the wirelike bodies themselves not to be firmly joined to the film layers and, for example, to be placed loosely between the film layers; the wirelike bodies may then held in the securing position by form-locking engagement with the film layers. In this regard, it is noted that a form-locking connection connects two elements together due to the shape of the elements themselves, as opposed to a force-locking connection, that locks the elements together by force external to the elements.
In a further embodiment, the wirelike bodies are secured on a substrate layer of the film with a securing layer of the film, which can be poured in between the wirelike bodies. In this embodiment as well, there are technological advantages in the production of the film. For example, the wirelike bodies can be placed on a film-like substrate layer or joined loosely to the substrate layer and, thereafter, a fluid or liquid, paste-like, powdered or granular filling material can be poured into the interstices between the wirelike bodies, to serve as the securing layer. The securing layer, which hardens firmly, joins the wirelike bodies to the substrate layer.
In a further embodiment, the wirelike bodies are joined to the film by being embedded in solidifiable material forming the film. This embodiment, just like the embodiments described hereinbefore, is distinguished by the fact that the wirelike bodies have an especially firm hold on the substrate layer. The solidification can be thermally, for example, by The wirelike bodies, in the production of the film from a fluid or liquid, paste-like, powdered or granular film material, can be placed in this film material, for example, and, after solidification of the film material, the wirelike bodies are firmly joined to the film.
In a further embodiment, the wirelike bodies have a curved-contoured profile. The advantage of this embodiment is that the film can be made using commercially available metal wires or plastic filaments as the wirelike bodies. Such wires or filaments as a rule have a circular cross section.
In a further embodiment, the plurality of low-wear zones formed as wirelike bodies are disposed so that a zonal spacing between respective pairs of mutually adjacent low-wear zones is less than a total width that includes two widths of adjacent support ribs. Such an arrangement of the low-wear zones relative to the dimensioning of the support ribs of the metering elements is possible, and inventive per se, not only in conjunction with low-wear zones embodied as wirelike bodies but also in conjunction with conventional low-wear zones of a corresponding ink-metering device in the prior art. In this manner, very good replicability of the metering setting or adjustment of metering elements is attained, each of the metering elements having two support ribs and a recess forming a metering gap, that is located between the support ribs. As a rule, the metering elements, which are arranged in a row, are disposed so close together than even if at least one of two support ribs is covered by a low-wear zone, tilting of the metering element is practically precluded.
In a further embodiment, the low-wear zones are disposed so that more than one of the low-wear zones at a time cover a support width of one and the same support rib. This embodiment is especially highly suitable both for metering elements having only a single support rib and for metering elements, respectively, having two support ribs. In the case of the metering elements with two support ribs, assurance is provided that each of both support ribs is covered at all times by a plurality of low-wear zones. With the latter embodiment, in which both support ribs, respectively, of a metering element are always covered by at least two low-wear zones at a time, a tilting motion of the metering element is absolutely reliably prevented, even if the gap between this metering element and an adjacent metering element allows a slight tilting motion.
In a further embodiment, the support width of the support rib is at least as large as a center-to-center spacing between two adjacent low-wear zones. This embodiment is especially advantageous in the case of low-wear zones embodied as wirelike bodies with a curved contoured profile, such as wires with a circular profile. Low-wear zones embodied in this manner are very reliably prevented from being displaced laterally away through the support rib by the pressure acting thereon. The center-to-center spacing of respective pairs of mutually adjacent low-wear zones is precisely equal to or less than the support width of a single one of the support ribs associated with the two low-wear zones. In the case wherein the two adjacent low-wear zones are associated with two adjoining support ribs of two adjacent metering elements, provision may be made for the center-to-center spacing of the two adjacent low-wear zones to be precisely equal to or less than the total width of the two immediately adjacent support ribs.
In a further embodiment, all of the low-wear zones of the film are disposed with identical spacing from one another. Preferably, all of the low-wear zones of the film are disposed with the same center-to-center spacing from one another. The spacings of respective adjacent low-wear zones from one another are thus constant not only locally in the region of the support ribs but also over the entire width of the film in the axial direction of the ink roller. This embodiment is advantageous with regard to manufacturing the film material. For example, when the film is cut to the size of an ink duct width, it is no longer necessary to devote any time for providing a correct association of the low-wear zones with the support ribs of the metering elements. Straightening of the film, so that low-wear zones grouped locally in the region of the support ribs are pushed into coincidence with the support ribs, is thus no longer necessary.
The invention can be employed in rotary printing presses which use direct or indirect planographic or letterpress printing. For example, the invention can be used in web-fed or sheet-fed offset printing presses. The ink roller is preferably the ink duct roller, belonging to an ink duct, of a vibrator-type or continuous-feed inking unit of the printing press.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in an ink-metering device in a printing press, it is nevertheless not intended to be limited to the details shown, since various modifications and changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, wherein: